Problem: $ { \left[\begin{array}{rr}{4} & {0} \\ {-2} & {4}\end{array}\right]-\left[\begin{array}{rr}{-1} & {-1} \\ {1} & {1}\end{array}\right] = {?} } $
Answer: To find the difference of two matrices, subtract the corresponding items between each matrix. ${\left[\begin{array}{rr}{4}-{-1} & {0}-{-1} \\ {-2}-{1} & {4}-{1}\end{array}\right]}$ Now, simplify: ${\left[\begin{array}{rr}{5} & {1} \\ {-3} & {3}\end{array}\right]}$